Ab initio study of the mechanisms of reactions of NF3 with aliphatic and benzylic substrates

At temperatures around 400 °C, nitrogen trifluoride (NF3) readily reacts with alkanes and benzene as well as ethers to produce stable N,N-difluoroamines. Difluoroamination of benzylic substrates results in initial N,N-difluoroamines that undergo eliminations or rearrangements. Toluene and ethylbenzene produce benzonitrile. Cumene produces α-methylstyrene. Diphenylmethane produces benzanilide. Little or no direct fluorination or radical dimerization is observed. This study uses ab initio calculations to help understand the reasons for such diverse reaction pathways.

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► Ab initio calculations explain why NF3 reacts with toluene at 400 °C to produce benzonitrile.
► Ab initio calculations indicate that NF3 reacts with ethylbenzene at 400 °C to produce benzonitrile and reacts with diphenylmethane at 400 °C to produce benzonitrile via radical Beckmann rearrangements.
► Ab initio calculations fail to explain why NF3 reacts with cumene at 400 °C to produce α-methylstyrene.
► Ab initio calculations do not show a significant difference for the resistance to elimination of HF by N,N-difluoroaminocyclohexane vs. α-N-N-difluoroaminotoluene.